Military operations require many different types of land vehicles. One type of military land vehicle is a high speed, high mobility, reconnaissance vehicle, for example, a High Mobility Multipurpose Wheeled Vehicle ("HMMWV"). All types of military land vehicles may encounter many, and at least three types, of explosives: (1) anti-tank mines, (2) anti-personnel mines and (3) claymores. In the case of these types of destructive devices, these devices may be detonated by the pressure of one or more of the tires or wheels of the vehicle rolling over them, or by remote detonation. The anti-tank and anti-personnel mines generally rely on pure blast pressure for destructive incapacitive effect. The claymores, on the other hand, have a lower blast pressure than that characteristic of the anti-tank mines. The claymores rely primarily on hundreds of flying shrapnel fragments for incapacitation effect. Thus, the underbody of military land vehicles should be constructed to withstand and/or deflect both pure blast pressure and flying shrapnel fragments to minimize damage to and deformation of the passenger compartment of the vehicle and thereby minimize the potential for injury to the vehicle occupants. Many models of a HMMWV are manufactured on an automotive type of chassis and do not, as manufactured, have the armor or structure to protect occupants of the HMMWV from mine blasts. Consequently, several armoring systems have been developed for an unarmored HMMWV.
One prior system for armoring the underbody of a HMMWV is shown in U.S. Pat. No. 4,326,445. In that patent, a plurality of armor protection plates attached to the underbody protect the frame members underneath of the vehicle from upwardly directed projectiles. Another prior system is described in U.S. patent application Ser. No. 08/262,768 for Armoring Assembly, filed Jun. 20, 1994 and assigned to the assignee of the present application. The described HMMWV armoring system is a blast pressure and shrapnel fragment defeating structure comprised of a fibrous material secured preferably to the upper surface of the floor area. In addition, a ballistic panel/blast shield is disposed below the floor and spaced therefrom so as to form an air gap therebetween. The above prior systems have improved the protection of personnel in the vehicle from the blast pressure and shrapnel. However, there is a continuing desire to provide even better armoring techniques and systems for protecting the passenger compartment of a vehicle against the blast pressures and shrapnel of larger mines, for example, anti-tank mines of 12 lbs. and above.